Carbon dioxide induced panic attacks and short term clonazepam treatment: preliminary study

et al. 2002

Arq. Neuro-Psiquiatr.

Self Cite

-Objective: We aim to determine if a treatment with a dose of clonazepam -2 mg/day, for 6 weeks, blocks spontaneous panic attacks and the ones induced by the inhalation of 35% carbon dioxide (CO 2 ) in panic disorder (PD) patients. The CO 2 challenge-test may be a useful addition tool for measuring the pharmacological response during the initial phase (6 weeks) in the treatment of PD. Method: Eighteen PD patients drug free for a week participated in a carbon dioxide challenge test. Fourteen had a panic attack and were openly treated for a 6-week period with clonazepam. At the end of the 6-week period they were submitted again to the CO 2 challenge test. Results: After 6 weeks of treatment with clonazepam, 12 of 14 PD patients (85.7%) did not have a panic attack after the CO 2 challenge test. Just 2 of 14 patients (14.3%) had a panic attack after the CO 2 challenge test. Ten of 14 (71.4%) PD patients had panic free status after clonazepam treatment. The 2 patients who had a panic attack in the sixth week, after the CO 2 test, did not have panic free status after the treatment with clonazepam. Conclusion: The CO 2 -test may be a valid tool for testing and predicting the drug response.

Section: Discussionsupporting

confidence: 93%

“…It is expected that clonazepam should block CO 2 induced anxiety attacks and other studies have reported similar results with chronic administration of clonazepam 18 and acute 19 and long term administration of alprazolam. 20 In a preliminary report 21 clonazepam was effective in blocking CO 2 panic attacks after 10 days of treatment.…”

mentioning

confidence: 94%

Carbon dioxide test as an additional clinical measure of treatment response in panic disorder

et al. 2002

Arq. Neuro-Psiquiatr.

Self Cite

“…Our previous study 19 with a CO2 challenge test in panic disorder patients suggest the efficacy of the short term clonazepam therapy in attenuating panic attacks and support the usefulness of the 35% carbon dioxide challenge test as an analogue method for study the efficacy of anti-panic drugs. For sure both test needs more research with a large number of patients to help elucidate the neurobiologic vulnerability of panic disorder patients and may lead to the development of more specific and effective treatments.…”

Section: Discussionsupporting

confidence: 62%

Panic disorder and hyperventilation

et al. 1999

Arq. Neuro-Psiquiatr.

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-Respiratory abnormalities are associated with anxiety, particularly with panic attacks. Symptoms such as shortness of breath, "empty-head" feeling, dizziness, paresthesias and tachypnea have been described in the psychiatric and respiratory physiology related to panic disorder. Panic disorder patients exhibit both behaviorally and physiologically abnormal responses to respiratory challenges tests. Objective: We aim to observe the induction of panic attacks by hyperventilation in a group of panic disorder patients (DSM-IV). Method: 13 panic disorder patients and 11 normal volunteers were randomly selected. They were drug free for a week. They were induced to hyperventilate (30 breaths/min) for 3 minutes. Anxiety scales were taken before and after the test. Results: 9 (69.2%) panic disorder patients and one (9.1%) of control subjects had a panic attack after hyperventilating (p< 0.05). Conclusion: The panic disorder group was more sensitive to hyperventilation than normal volunteers. The induction of panic attacks by vonluntary hyperventilation may be a useful and simple test for validating the diagnosis in some specific panic disorder patients.KEY WORDS: panic attack, respiration, anxiety disorder, ventilation. Transtorno do pânico e hiperventilaçãoRESUMO -Distúrbios respiratórios estão associados à ansiedade, especialmente aos ataques de pânico. Sufocamento, sensação de "cabeça leve", tonteira, parestesias e taquipnéia aparecem na descrição psiquiátrica e respiratória do transtorno do pânico. Pacientes com transtorno do pânico apresentam respostas comportamentais e fisiológicas anormais a testes respiratórios. Objetivo: Observamos a indução de ataques de pânico através de hiperventilação em um grupo de pacientes com transtorno do pânico (DSM-IV). Método: Selecionamos de forma randomizada 13 pacientes com transtorno do pânico e 11 voluntários normais. Todos estavam sem medicação há uma semana. Foram induzidos a hiperventilar (30 inspirações/minuto) durante 3 minutos. Escalas de ansiedade foram utilizadas antes e após o teste. Resultados: No grupo com transtorno de pânico, 9 (69,2%) pacientes apresentaram ataque de pânico após a hiperventilação e apenas 1 (9,1%) no grupo controle (p<0,05). Conclusão: Os pacientes com transtorno do pânico foram mais sensíveis à hiperventilação que o grupo controle. A indução de ataques de pânico através da hiperventilação pode ser método útil e simples para validar o diagnóstico em um grupo específico de pacientes com transtorno do pânico.PALAVRAS CHAVE: ataque de pânico, respiração, transtorno de ansiedade, ventilação.One of the features of the description of a panic attack is the physical nature of the symptoms. Patients with panic disorder always begin the description of their disease mentioning either the respiratory system, the heart or the gastrointestinal tract 1 . Symptoms such as shortness of breath,The research was conducted at

“…The inhalation of high carbon dioxide (CO 2 ) concentrations has consistently been shown to provoke anxiety and panic attacks in panic disorder (PD) patients (1)(2)(3)(4)(5)(6)(7). Among the numerous agents capable of inducing panic in patients with PD, CO 2 offers significant advantages.…”

Section: Introductionmentioning

confidence: 99%

Respiratory panic disorder subtype and sensitivity to the carbon dioxide challenge test

et al. 2002

Braz J Med Biol Res

The aim of the present study was to verify the sensitivity to the carbon dioxide (CO 2 ) challenge test of panic disorder (PD) patients with respiratory and nonrespiratory subtypes of the disorder. Our hypothesis is that the respiratory subtype is more sensitive to 35% CO 2 . Twenty-seven PD subjects with or without agoraphobia were classified into respiratory and nonrespiratory subtypes on the basis of the presence of respiratory symptoms during their panic attacks. The tests were carried out in a double-blind manner using two mixtures: 1) 35% CO 2 and 65% O 2 , and 2) 100% atmospheric compressed air, 20 min apart. The tests were repeated after 2 weeks during which the participants in the study did not receive any psychotropic drugs. At least 15 of 16 (93.7%) respiratory PD subtype patients and 5 of 11 (43.4%) nonrespiratory PD patients had a panic attack during one of two CO 2 challenges (P = 0.009, Fisher exact test). Respiratory PD subtype patients were more sensitive to the CO 2 challenge test. There was agreement between the severity of PD measured by the Clinical Global Impression (CGI) Scale and the subtype of PD. Higher CGI scores in the respiratory PD subtype could reflect a greater sensitivity to the CO 2 challenge due to a greater severity of PD. Carbon dioxide challenges in PD may define PD subtypes and their underlying mechanisms.